Propionamide antitumor agents

ABSTRACT

The present invention encompasses compounds of the formula ##STR1## AND THE PHARMACEUTICALLY ACCEPTABLE ACID ADDITION SALTS THEREOF WHEREIN R represents hydrogen or hydroxymethyl. The compounds of the present invention are prepared by condensing N-carbobenzyloxyserine or 2-carbobenzyloxyamino-3-hydroxy-2-hydroxymethylpropionic acid with p- N,N-bis(2-chloroethyl)!phenylenediamine hydrochloride and removing the carbobenzyloxy protecting group by catalytic hydrogenation. These compounds are useful as cytotoxic agents, in particular, antitumor agents.

Compounds of the present invention are prepared according to the reaction Schemes A and B as follows: ##STR2## ##STR3##

Thus in Scheme A L-serine is protected by reaction with benzylcloroformate under Schotten-Bauman conditions. This protected serine is reacted with p- N,N-bis(2-chloroethyl)!phenylendiamine in the presence of N,N-dicyclohexyl carbodiimide in anhydrous methylene chloride and the product of that reaction is deprotected by hydrogenation over 5% palladium on charcoal at room temperature and pressure to provide 2-amino-N- p-bis(2-chloroethyl)amino!phenyl-3-hydroxypropionamide. The hydrogenation is carried out in methanol and an appropriate acid is added to the methanol; the corresponding acid salt such as the hydrochloric acid salt is obtained. Replacement of hydrochloric acid with pharmaceutically acceptable acids such as sulfuric, phosphoric, hydrobromic, hydriodic, sulfamic, citric, lactic, maleic, malic, succinic, tartaric, cinnamic, acetic, benzoic, gluconic, ascorbic, and related acids provide salts of compounds of the present invention.

In Scheme B serine is converted to 2-amino-3-hydroxy-2-hydroxymethylpropionic acid by reaction with aqueous sodium carbonate containing an excess of formaldehyde. From that point the synthesis is conducted as set out in Scheme A. However, it is preferable to activate 2-amino-3-hydroxy-2-hydroxymethylpropionic acid with 1-hydroxy benzotriazole to facilitate condensation with p- N,N-bis(2-chloroethyl)!phenylendediamine. The product, 2-amino-N- p-bis(2-chloroethyl)amino!phenyl-3-hydroxy-2-hydroxymethylpropionamide, is isolated as the hydrochloride salt. As in Scheme A, the hydrochloric acid may be replaced with those indicated acids.

Antitumor acitvity of the compounds of the present invention is illustrated by their ability to inhibit EL4 and SB2 lymphomas in mice. Thus, buffered saline solutions of 2-amino-N- p-bis(2-chloroethyl)amino!phenyl-3-hydroxy-2-hydroxymethylpropionamide hydrochloride II and 2-amino-N- p-bis(2-chloroethyl)amino!phenyl-3-hydroxypropionamide hydrochloride I in amounts indicated as follows are administered to mice challenged with the indicated tumor.

    ______________________________________                                    MEDIAN                        AMOUNT      SURVIVAL     TUMOR  COMPOUND    (μg)     TIME(DAYS)     ______________________________________     EL4    Saline      --          13            I            50         19            "            75         21            "           100         22            "           125         21            "           150         23            II           50         15            "           100         19            "           200         21            "           300         22     SB2    Saline      --          12            I            50         16            "            75         17            "           100         >40            "           125         >40            "           150         >40            II           50         15                        100         15                        200         16                        300         >40     ______________________________________

Compounds of the present invention can be used in regimens as described for chlorambucil, 0.1-0.2 mg per kg by mouth daily for 3-6 weeks as described in Cuttings Handbook of Pharmacology, 4th edition, page 135, Appleton-Century-Crofts, N.Y., N.Y., 1969. Those skilled in the pharmaceutical arts will recognize the dosage range will vary according to route of administration and individual differences in tolerances to toxic side effects. Thus, dosage ranges of 0.01-1.0 mg/kg are contemplated in the present invention.

The nearest prior art appears to be a compound of the formula ##STR4## Chem. Abs. 55, 7325 i (1961). Compounds of the present invention are particularly distinct in that either one or two of the hydrogens on the glycyl carbon in the above formulae are replaced with hydroxymethyl.

The following examples are presented to further illustrate the present invention. They should not be construed as limiting it either in spirit or in scope. In these examples quantities are indicated in parts by weight unless parts by volume are specified, and temperatures are indicated in degrees Centigrade (° C). The relationship between parts by weight and parts by volume is the same as that existing between grams and milliliters.

EXAMPLE 1

2.39 Parts of N-carbobenzyloxy-L-serine and 2.69 parts of p- N,N-bis(2-chloroethyl)!phenylenediamine hydroxhloride were stirred together at room temperature and in the dark as a suspension in 50 parts by volume of dry methylene chloride. Then 1.01 parts of distilled triethylamine was added and stirring was continued for 30 minutes. A solution of 2.16 parts of N,N-dicycohexylcarbodiimide in 50 parts by volume of dry methylene was added over 10 minutes. Stirring was continued for 24 hours to provide a dark solution and a white precipitate. The reaction mixture was filtered and the filtrate was successively washed with aqueous sodium bicarbobate, 2 molar hydrochloric acid, and water. The organic layer was then dried over sodium sulfate and filtered and removal of solvent in vacuo provided a crude solid which after recrystallization from acetone/hexane or toluene provided 2-carbobenzyloxyamino-N- p-bis(2-chloroethyl)amino!phenyl-3-hydroxypropionamide, melting at 145°-146° and having the following structural formula ##STR5##

0.85 Parts of this material was dissolved in 85 parts by volume of distilled methanol containing 0.2 parts by volume of concentrated lhdrochloric acid and the solution hydrogenated at room temperature and atmospheric pressure over 0.17 parts of a 5% palladium-on-charcoal calalyst. The catalyst was removed by filtration, the solvent removed in vacuo, and the product was precipitated upon addition of dry ether. 2-Amino-N- p-bis(2-chloroethyl)-amino!phenyl-3-hydroxypropionamide hydrochloride is isolated as a hydroscopic solid having the formula ##STR6##

Replacement hydrochloric acid with an equivalent amount of sulfuric, phosphoric, hydrobromic, hydriodic, sulfamic, citric, lactic, maleic, malic, russinic, tartaric, cinnamic, acetic, benzoic, gluconic, ascorbic acid provide the corresponding acid addition salt. Neutralization of the acid salt with base and extraction with ether provides the free base, 2-amino-N- p-bis(2-chloroethyl)amino!phenyl-3-hydroxypropionamide. ##STR7##

EXAMPLE 2

5.9 Parts of DL-serine was dissolved in 1100 parts by volume of 0.2 molar sodium carbonate. 5.6 parts by volume of a 1.0 molar cupric sulfate solution was then added, followed by 34 parts by volume of 40% aqueous formaldehyde solution. The solution was then heated at 95°-100° C for 20 minutes and a precipitate of copper resulted.

The reaction mixture was allowed to cool to room temperature and then filtered to remove the precipitated copper. After acidification with glacial acetic acid, the solution was concentrated under reduced pressure to around 100 parts by volume and then poured onto a Zeolite 225 ion exchange column, H form. This was washed with water until the acid band disappeared, when the column was eluted with 2M ammonium hydroxide, collecting and combining those fractions which gave a positive ninhydrin reaction. These fractions were then concentrated in vacuo, when IMS (95% ethanol) was added to precipitate the required product. After standing at 0° C for 3 days the crude product was filtered off, washed with IMS, and then recrystalized from IMS/water to afford 2-amino-3-hydroxy-2-hydroxymethylpropionic acid, melting at 253°-254° C and having the following structural formula ##STR8## 19.20 parts of this propionic acid is reacted with 21.56 parts of volume of N-benzylchloroformate in 236 parts by volume of N-benzylchloroformate in 236 parts by volume of sodium bicarbonate containing 29.8 parts of sodium carbonate. Following the procedure set out in Example 1, 2-carbobenzyloxyamino-3-hydroxy-2-hydroxymethylpropionic acid, melting at 109°-112° C (lit 112°-114°) is isolated. This compound has the following structural formula ##STR9##

1.0 parts of this material were placed with 1.1 parts of p- N,N-bis(2-chloroethyl)!phenylenediamine hydrochloride in 20 parts by volume of methylene chloride. 0.418 Parts of distilled triethylamine was added with continuing stirring and after stirring for 10 minutes 0.85 parts of N,N-dicyclohexylcarbodiimide in 20 parts by volume of dry methylene chloride was added over a 10 minute period. The reaction was worked up as in Example 1 to provide 2-carbobenzyloxyamino-N- p-bis(2-chloroethyl)amino!phenyl-3-hydroxy-2-hydroxymethylpropionamide, melting at 138°-141° C, and having the following structural formula ##STR10##

Using equivalent quantities and following the procedures in Example 1, 0.5 parts of this material is catalytically hydrogenated over 5% palladium-on-charcoal catalyst to provide 2-amino-N- p-bis(2-chloroethyl)amino!-phenyl-3-hydroxy-2-hydroxymethylpropionamide hydrochloride having the following structural formula ##STR11##

Other pharmaceutically acceptable acid addition salts and the free base 2-amino-N- p-bis(2-chloroethyl)-amino!phenyl-3-hydroxy-2-hydroxymethylpropionamide are prepared as described in Example 1.

Alternatively, 5.20 parts of 2-carbobenzyloxyamino-3-hydroxy-2-hydroxymethylpropionic acid and 5.95 parts of 1-hydroxy benzotriazole in 130 parts by volume of dry methylene chloride are reacted. To this reaction mixture was added 4.03 parts of N,N-dicyclohexylcarbodimide and stirring continued for 16 hours. Then 5.7 parts of p- N,N-bis(2-chloroethyl)!phenylenediamine hydrochloride and 2.99 parts by volume of triethylamine are added and stirred for 65 hours and worked up as earlier described to provide 2-carbobenzyloxyamino-N- p-bis (2-chloroethyl)-amino!-phenyl-3-hydroxymethylpropionamide. 

What is claimed is:
 1. A compound of the formula ##STR12## wherein R is hydrogen or hydroxymethyl.
 2. A compound according to claim 1 which is 2-amino-N- p-bis(2-chloroethyl)amino!-phenyl-3-hydroxypropionamide.
 3. A compound according to claim 1 which is 2-amino-N- p-bis(2-chloroethyl)amino!-phenyl-3-hydroxy-2-hydroxymethylpropionamide. 